Why do some metal ions spontaneously form nanoparticles in water microdroplets? Disentangling the contributions of the air-water interface and bulk redox chemistry.

ABSTRACT: Water microdroplets containing 100 μM HAuCl₄ have been shown to reduce gold ions into gold nanoparticles spontaneously. It has been suggested that this chemical transformation takes place exclusively at the air-water interface of microdroplets, albeit without mechanistic insights. We compared the fate of several metallic salts in water, methanol, ethanol, and acetonitrile in the bulk phase and microdroplet geometry (sprays). Experiments revealed that when HAuCl₄ (or PtCl₄) is added to bulk water (or methanol or ethanol), metal NPs appear spontaneously. Over time, the nanoparticles grow, evidenced by the bulk solutions' changing colors. If the bulk solution is sprayed pneumatically and microdroplets are collected, the NP size distribution is not significantl

SUBMITTER: Eatoo MA 

PROVIDER: S-EPMC11603139 | biostudies-literature | 2025 Jan

REPOSITORIES: biostudies-literature